Mercedes W114 250 Coupe - help!

[Bellow]

The subframe shape was changed slightly in facelift 107's to accommodate the sump of the M103. Not a lot and a big hammer would do the job but it's not a straight drop-in.

What needs to change and what is the position re electronics? (Does a M104 with auto box run (with its own ECU) when removed from the donor car - unlike more modern drivetrains where all sorts of external sensors (eg wheel speed) are employed?)

With the grinder (I love the smell of burning hair in the morning)

I won't ask further but recently using mine (while wearing a hat - cunningly!) I had those myriad little burning sensations down my neck! Not pleasant!

burning metal grinds and glass form a really solid bond, s

Welding spatter also. Which is what anti-spatter paste is for. (A bit late I know - unless you have more windows to attack).

Yes the M104 is the unit I had in mind though DRUK says not a straight drop in. There's something about that engine that appeals to me though I can't quite put my finger on why. It in a W123 appeals for some reason.
Going ever more left-field. 2.5 Cosworth? That notion no doubt comes from a Mk1 Cortina a mate had with a BDA fitted.

 

[Charles Morgan]

I did have the idea of a Dino 2.4 V6 but then decided on cost grounds (both purchase and subsequent maintenance) that this was possibly a bit silly. Having seen the appalling build quality of a Fiat Dino coupe at close quarters recently something appealed about the idea of a proper coupe with that flat out stunning engine. A Maserati V6 from an SM also appealed but that like the Cosworth idea fails on the one count that I have both in my fleet already.

The 24v 104 is very charismatic, lovely revvy engine with just a bit more character than the later 3.2 104 at the expense of low end torque. I love straight sixes (two in the fleet already) so I see entirely where you're coming from Bellow. Perhaps a BMW M30?

 

[Charles Morgan]

From what I recall according to one guy in the States the M117 drops straight in the W114/5 provided an M117 sump pan, engine mount arms & oil filter housing are used from the V8 R107 along with custom exhaust manifolds. As already mentioned the W115 & the R107 seemingly share the same front cross member.

Further research indicates it might be more difficult.

On the other hand, sounds like a small block Chevy would have no problem (internal camshafts).

Now all I need to do is to find the right shade of pink paint for Derek...

 

[Bellow]

Would a M104 with its 4-valve/cylinder bulk be too tall for the W114's bay?
At least one thing that the older (though even a recent - Chevy I think) V8s have going for them is compactness due to being pushrod motors. In my mind I accept 2-valve/cylinder if it's delivered in a simple compact package and if the complexity and bulk of OHC is to be entertained then be as well go all the way with 4-valve/cylinder. DOHC heads are huge - and heavy. And that's before the addition of VVT mechanisms. It's at this point I usually fall back in love with the 2-stroke. I'll try and contain myself....

 

[Bellow]

I did have the idea of a Dino 2.4 V6 but then decided on cost grounds (both purchase and subsequent maintenance) that this was possibly a bit silly. Having seen the appalling build quality of a Fiat Dino coupe at close quarters recently something appealed about the idea of a proper coupe with that flat out stunning engine. A Maserati V6 from an SM also appealed but that like the Cosworth idea fails on the one count that I have both in my fleet already.

The 24v 104 is very charismatic, lovely revvy engine with just a bit more character than the later 3.2 104 at the expense of low end torque. I love straight sixes (two in the fleet already) so I see entirely where you're coming from Bellow. Perhaps a BMW M30?

Bizarrely, I have the copy of Car magazine with a group test of the W114 saloon (with M110) pitted against a BMW 3.0 and Fiat 130 - equipped with that V6.

 

[Charles Morgan]

The Fiat 130 has a different V6 (oddly!) - it is a Lampredi designed 2.9 - 3.2 engine, not as frenetic as the Dino.

What was the test result? I bet they plumped for the BMW, Car of that period liked Mercs but were less enthused about their handling and engine charisma.

 

[Bellow]

The MB got the nod.
''...for unhurried comfort and more evidence of where the £4000 went, the Fiat 130 makes sense. The Merc does not look like £4000 inside or outside, but it feels like it on the road. And the BMW fits in between the two which makes it a compromise hard to ignore. If the suspension was better controlled with less squat then this would be our number one choice. Meantime the 280E just scrapes it as our selection.''

Dynamically the 280E was rated some way ahead of the BMW (3.0S). Better calibrated and more feelsome steering, neutral handling - no surprises (BMW could snap oversteer), ''extremely agile'' and no unpredictably no matter surface or speed.
The Fiat did indeed have the 3.2 V6 - the least powerful of the trio with 165hp and lugging the heaviest car around was the slowest of the bunch.

 

[Charles Morgan]

I have found the review. It seems to bear out what Druk has said about the M110. I wonder if the toppy nature of its performance is the start of the autobahn need for speed.

 

[Bellow]

The same review from the May 1973 edition? Where did you unearth that?!!!
Car figured that the reason for the M110 fitment was BMW's 'recent' success with its 2500 and 3.0 models. The 3.0S tested had a stronger top end than the 280 so the chase began there I guess. MB's first twin cam (per bank) for the road?

 

[grober]

My concern with V8 configuration engines that they might interfere with the tubular bulkhead to spring perch bracing. Their removal would weaken the structural rigidity of the front body cell without further re-inforcement?
see this picture???

 

[Charles Morgan]

What we really need at this point is someone to photoshop an M116 4.2 V8 into the engine bay and see what happens.

I see the problem instantly Graeme. I wonder what an equivalent 107 engine bay would reveal.

 

[Bellow]

It's hard to be certain, but the M110 engined W114 appears not to have them. The bulk of its head would preclude them I suspect. Perhaps its shell is reinforced somewhere else eg bulkhead, flitches. Only a slim straight (or very compact V8) is going to fit between them if they have to stay (I don't do puns BTW).

 

[grober]

Well I think I can supply the answer here. You have to get rid of the braces as this pictorial thread illustrates-- its a good un. 1976 Mercedes 240D M117 5.5 liter | Retro Rides
a sample

 

[Charles Morgan]

Here's a blog about fitting a small block Chevvy.

That one is tremendously helpful Graeme!

 

[Bellow]

He just severed them! In fairness, the load path from engine mounts to springs is direct and doesn't involve the bulkhead.
Here...

it appears to be a W114/5 (clap hands wipers) with M110 and no sign of stays.

Eh!

 

[Charles Morgan]

That's an M104. Ummm...

 

[stwat]

That's an M104. Ummm...

3.6 AMG ? MMMMMMMmmmmmmmmmmmmm

 

[Charles Morgan]

I've found his album - this is helpful too

 

[Bellow]

M104 indeed. And with a potential of 3.6litres. Does the M103 sump fit the M104 (with change of suction pipe)? Pity the W114 has that crossmember. A W123 doesn't. I would imagine arranging the exhaust for a straight six will be a lot easier than for a V8. That and the final drive ratio would be swaying me toward a six.

The M104 installation is on Peachparts forum but I could only find his intro thread. The builder said he would build a build thread though. There was talk of there being no room in the tunnel for a 'large' auto box (the builder was intent on using a Getrag manual) but if that's true then there would be implications for other auto boxes - assuming auto is a preference. The thread was full of naysayers mind.

 

[John Jones Jr]

Further research indicates it might be more difficult.

See photo.